The LTC2411, a differential input No Latency ?Σ? 24-Bit ADC in MSOP is featured on the DC358A demonstration board. The LTC2411 features 2-ppm linearity, 4-ppm full-scale accuracy, 1-ppm offset accuracy, and 0.29-ppm RMS noise. The LTC2411 operates from 2.7 to 5.5V supplies, drawing less than 300 uA of current and 2uA sleep mode current. It provides normal mode line frequency rejection of 110 dB, and DC and line frequency common mode rejection of 140 dB. Single conversion settling time yields latency-free results, thus enables multiplexing , correlated double sampling and other interleaved sampling schemes. The LTC2411 performs auto-zero and calibration in every output result, which are transparent to the user. The device does not require initialization. The board includes a precision 2.5V band gap reference (LT1019-2.5), and a precision 5V buried zener reference (LT1236-5), as well as bypassing capacitors, and jumpers to select line frequency rejection and various on board /external references. The demonstration board is designed to interface to a personal computer, as well as give an example of good placement of bypass and partitioning of an analog and digital ground. The demo board allows the user to quickly evaluate the LTC2411 performance while demonstrating its ease of use. The board connects directly to the RS232C port of any IBM compatible PC. The demo board derives its power from the RS232 port. The on board LT1236 ordinarily powers the LTC2411, and may be used as a 5V reference. Alternatively, the 2.5V reference may be used as reference, and the 5V output from the LT1236 may be used as excitation for a bridge application, although, an external power supply is likely required in this case. The 2.5V output from the LT1261 can also be used as a bias source for sensing single ended bipolar signals that must be able to accommodate the full +/- 2.5V input range. If, for example, an instrumentation amplifier were to be used to drive the demo board, the reference terminal of the instrumentation amplifier can be connected to the 2.5V output. Alternatively a differential amplifier scheme can be biased such that its differential outputs are centered at 2.5V. The software included in this package presents a 7.5 digit display, as well as a histogram display, and calculated noise figure , all updated in real time. The demonstration program also provides averaging capability, zero and full scale cal functions, and raw data output to a file, for off line evaluation. The demo board has a group of banana jacks for 6 wire connections to a bridge or other source, as well as a group of turrets for connection to external power. See schematic.